Question

In a school, no student has scored less than 25 marks or more than 60 marks in an examination. Their cumulative frequencies are as follows:

Less than	60	55	50	45	40	35	30
Total frequency	120	115	90	75	65	45	32

Find the frequencies in the class intervals 25−30, 30−35,....55−60.

Answer 1

Marks	Cumulative Frequency
Less than 60 Less than 55 Less than 50 Less than 45 Less than 40 Less than 35 Less than 30	120 115 90 75 65 45 32

This can be presented in the form of a simple frequency distribution as follows.

Marks	Number of Students
25 − 30 30 − 35 35 − 40 40 − 45 45 − 50 50 − 55 55 − 60	32 45 − 32 = 13 65 − 45 = 20 75 − 65 = 10 90 − 75 = 15 115 − 90 = 25 120 − 115 = 5